Rab Ascent -18 °C

ISO comfort -10 °C for £390 or less: 880 g of 650 FP hydrophobic duck down in a roomy wide mummy.

Best price found

£347.55

at Hardloop · RRP £409.90 · Left zip sold out; right zip not marked sold out · was £409.90

Prices checked 31 October 2026. We may earn a commission on these links.

Specifications

Weight: 1,650 g (regular)
Packed size: 26 × 45 cm
Comfort: Comfort -10 °C / limit -18 °C
Fill: 650 FP duck down, 880 g fill
Shell & construction: 20D Pertex Quantum nylon ripstop (38 g/m²) with fluorocarbon-free DWR; recycled 20D nylon lining; L.O.F.T. construction with sidewall baffles
Rating Standard: ISO 23537 rating
Fill Note: 650FP European duck down with Grangers fluorocarbon-free hydrophobic finish. Regular, Long and Wide sizes, left or right zip. Hand-filled in Derbyshire.
Season: 4-season / Scottish winter
Zip: Two-way YKK 3/4-length main zip with synthetic-filled baffle, plus a short arm zip

ISO comfort -10 °C, five degrees warmer than the Ascent -12 °C, for £30 more at Rab
Wide mummy cut leaves room for a down jacket inside on the coldest nights
Short second zip lets you use your arms, e.g. to cook, while staying zipped in
1650 g and 26 × 45 cm packed: Rab's Neutrino -18 °C gets the same rating in 1280 g (at £670)
Main zip is only 3/4 length, so it vents less well on milder nights